var dom = document.getElementById ? true:false;
var nn4 = document.layers ? true:false;
var ie4 = document.all ? true:false;


if(ie4){
	showhide = new Array('hidden','visible');
}
else if(nn4){
	showhide = new Array('hide','show');
}
else if(dom){
	showhide = new Array('hidden','visible');
}


function pop(doc)
{
	win=window.open("pop.php","","height=480,width=700,location=no,status=no,menubar=no,scrollbars=yes");
}


function img_show(layer_id)
{
	if(ie4){
		document.all.tags("div")[layer_id].style.visibility=showhide[1];
	}
	else if(nn4){
		document.layers[layer_id].visibility=showhide[1];
	}
	else if(dom){
		document.getElementById("L"+layer_id).style.visibility=showhide[1];
	}
}


function img_hide(layer_id)
{
	if(ie4){
		document.all.tags("div")[layer_id].style.visibility=showhide[0];
	}
	else if(nn4){
		document.layers[layer_id].visibility=showhide[0];
	}
	else if(dom){
		document.getElementById("L"+layer_id).style.visibility=showhide[0];
	}
}


function menu_show(layer_id)
{
	menu_hide();
	if(ie4){
		document.all.tags("div")[layer_id].style.visibility=showhide[1];
	}
	else if(nn4){
		document.layers[layer_id].visibility=showhide[1];
	}
	else if(dom){
		document.getElementById("L"+layer_id).style.visibility=showhide[1];
	}
}


function menu_hide()
{
	for(i=0;i<=7;i++){
		if(ie4){
			document.all.tags("div")[i].style.visibility=showhide[0];
		}
		else if(nn4){
			document.layers[i].visibility=showhide[0];
		}
		else if(dom){
			document.getElementById("L"+i).style.visibility=showhide[0];
		}
	}
}